1. Field
The present embodiments generally relate to apparatus and methods for separating particulate-fluid suspensions. More particularly, embodiments of the present invention relate to apparatus and methods for separating particulate-fluid suspensions and stripping the settled particulates within a single vessel.
2. Description of the Related Art
Cyclonic separation has been used to separate a mixture or suspension containing at least two components with differing densities, for example suspensions of particulates in a carrier fluid. The separation is typically accomplished by introducing the solid/fluid suspension to a generally cylindrical separator on a tangential axis to the separator. The centrifugal force generated by the tangential introduction of the suspension to the separator results in the accumulation of a dense solid phase along the walls of the separator, and, through centripetal motion, a less dense fluid phase in the center of the separator. In a traditional cyclonic separator, the solids can flow along the walls of the separator, accumulating at a low point in the separator for removal, while the relatively solids-free fluid can be withdrawn from the center of the separator. Such cyclonic separation methods can be used to purify a solid or fluid phase, to concentrate a solid or fluid phase, to terminate chemical and physical interactions between mixed phases, or any combination thereof.
As with most separation processes, the cyclonic separation of a suspension into independent fluid and solid phases, can result in the entrapment and adsorption of fluid in the accumulated solids within the separator. Accordingly, because of high reaction rates in catalytic cracking applications, an important consideration in cyclonic separation of light hydrocarbon products from the coke-covered particulate catalyst is the displacement of the entrapped and/or adsorbed light hydrocarbons from the separated particulate catalyst. Displacement of any entrapped or adsorbed light hydrocarbons from the separated particulate catalyst will minimize side-reactions between the catalyst and any residual light hydrocarbons present in the settled particulate catalyst, thereby helping to control conversion product profiles and to minimize additional “delta coking” on the surface of the particulate catalyst.
A need, therefore, exists for new apparatus and methods for separating a suspension containing a fluid and solid particulates, while stripping entrained fluid and adsorbed hydrocarbons from the separated solids prior to removal from the separator.